Date: |
Flight Nr. |
Take-off: |
Landing: |
Duration: |
Pilot: |
12.10.42 |
30 |
1030 |
1046 |
16' |
Bartsch
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Condition: |
Production
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Engine BMW 801 D II/25453
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Tight engine cowl.
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Split flaps with measuring system for the opening angle.
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px and px Δ measuring equipment.
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1.) |
Measurement of the stiffness of the split flap actuator with or without pre-load.
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2.) |
Determination of the split flaps opening angle as a function of ram pressure.
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1.) |
In order to determine
the stiffness of the split flaps actuator, the opening force was
determined, as a function of the opening angle. The outer edge of the rear split flap L and R (viewed
in the direction of flight) was chosen as the point of attack for the
force.
The distance from the pivot point of the flap was ~ 85 mm. Force
direction was always perpendicular to the flap pivot point. In the
condition as delivered, the flap actuator was very soft (without
pre-load) resulting in a flap opening angle of already ~ 8° at a 40
kg load.
To modify this unacceptable condition for speed measurements, the
actuator has been changed so that now the flaps remain just closed at P
+ 40 kg (Graph sheet 1).
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2.) |
Graph sheet 2 shows the results obtained in flight.
With a Va = 500 km/h the split flaps set up under 40 kg pre-load remain just closed, while the flaps left in the delivery condition
already show 11,5° opening angle. At Va = 750 km/h also the pre-loaded flaps open up, namely to ~ 9°, this corresponds to a load of ~ 70 kg according to Graph 1.
It is important to ensure that the split flaps remain closed at least up to the maximum level ram pressures (q = 1500).
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The split flaps actuator already clatters after a short
time of operation, the bolts of the small flap drive levers must then be
strengthened and replaced.
In addition, the foundation of the mounting on apparatus bay door is much too soft.
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Wenzendorf, 13 October 1942
Gt/Kl.
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